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Unmap(),Protect(): Removed goto programming by a do {} while loop. Also fixed

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problem with potential integer overflow at the end of the address space.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37190 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Ingo Weinhold 2010-06-21 13:57:00 +00:00
parent 66f9974b06
commit a19f81b6c7
1 changed files with 83 additions and 89 deletions
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172
src/system/kernel/arch/x86/paging/32bit/X86VMTranslationMap32Bit.cpp
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@ -211,57 +211,53 @@ X86VMTranslationMap32Bit::Map(addr_t va, phys_addr_t pa, uint32 attributes,
status_t
X86VMTranslationMap32Bit::Unmap(addr_t start, addr_t end)
{
page_directory_entry *pd = fPagingStructures->pgdir_virt;
start = ROUNDDOWN(start, B_PAGE_SIZE);
end = ROUNDUP(end, B_PAGE_SIZE);
TRACE("unmap_tmap: asked to free pages 0x%lx to 0x%lx\n", start, end);
restart:
if (start >= end)
return B_OK;
int index = VADDR_TO_PDENT(start);
if ((pd[index] & X86_PDE_PRESENT) == 0) {
// no pagetable here, move the start up to access the next page table
start = ROUNDUP(start + 1, B_PAGE_SIZE * 1024);
if (start == 0)
return B_OK;
goto restart;
}
TRACE("unmap_tmap: asked to free pages 0x%lx to 0x%lx\n", start, end);
struct thread* thread = thread_get_current_thread();
ThreadCPUPinner pinner(thread);
page_directory_entry *pd = fPagingStructures->pgdir_virt;
page_table_entry* pt = (page_table_entry*)fPageMapper->GetPageTableAt(
pd[index] & X86_PDE_ADDRESS_MASK);
for (index = VADDR_TO_PTENT(start); (index < 1024) && (start < end);
index++, start += B_PAGE_SIZE) {
if ((pt[index] & X86_PTE_PRESENT) == 0) {
// page mapping not valid
do {
int index = VADDR_TO_PDENT(start);
if ((pd[index] & X86_PDE_PRESENT) == 0) {
// no page table here, move the start up to access the next page
// table
start = ROUNDUP(start + 1, kPageTableAlignment);
continue;
}
TRACE("unmap_tmap: removing page 0x%lx\n", start);
struct thread* thread = thread_get_current_thread();
ThreadCPUPinner pinner(thread);
page_table_entry oldEntry
= X86PagingMethod32Bit::ClearPageTableEntryFlags(&pt[index],
X86_PTE_PRESENT);
fMapCount--;
page_table_entry* pt = (page_table_entry*)fPageMapper->GetPageTableAt(
pd[index] & X86_PDE_ADDRESS_MASK);
if ((oldEntry & X86_PTE_ACCESSED) != 0) {
// Note, that we only need to invalidate the address, if the
// accessed flags was set, since only then the entry could have been
// in any TLB.
InvalidatePage(start);
for (index = VADDR_TO_PTENT(start); (index < 1024) && (start < end);
index++, start += B_PAGE_SIZE) {
if ((pt[index] & X86_PTE_PRESENT) == 0) {
// page mapping not valid
continue;
}
TRACE("unmap_tmap: removing page 0x%lx\n", start);
page_table_entry oldEntry
= X86PagingMethod32Bit::ClearPageTableEntryFlags(&pt[index],
X86_PTE_PRESENT);
fMapCount--;
if ((oldEntry & X86_PTE_ACCESSED) != 0) {
// Note, that we only need to invalidate the address, if the
// accessed flags was set, since only then the entry could have
// been in any TLB.
InvalidatePage(start);
}
}
}
} while (start != 0 && start < end);
pinner.Unlock();
goto restart;
return B_OK;
}
@ -641,9 +637,9 @@ status_t
X86VMTranslationMap32Bit::Protect(addr_t start, addr_t end, uint32 attributes,
uint32 memoryType)
{
page_directory_entry *pd = fPagingStructures->pgdir_virt;
start = ROUNDDOWN(start, B_PAGE_SIZE);
if (start >= end)
return B_OK;
TRACE("protect_tmap: pages 0x%lx to 0x%lx, attributes %lx\n", start, end,
attributes);
@ -657,62 +653,60 @@ X86VMTranslationMap32Bit::Protect(addr_t start, addr_t end, uint32 attributes,
} else if ((attributes & B_KERNEL_WRITE_AREA) != 0)
newProtectionFlags = X86_PTE_WRITABLE;
restart:
if (start >= end)
return B_OK;
page_directory_entry *pd = fPagingStructures->pgdir_virt;
int index = VADDR_TO_PDENT(start);
if ((pd[index] & X86_PDE_PRESENT) == 0) {
// no pagetable here, move the start up to access the next page table
start = ROUNDUP(start + 1, B_PAGE_SIZE * 1024);
if (start == 0)
return B_OK;
goto restart;
}
struct thread* thread = thread_get_current_thread();
ThreadCPUPinner pinner(thread);
page_table_entry* pt = (page_table_entry*)fPageMapper->GetPageTableAt(
pd[index] & X86_PDE_ADDRESS_MASK);
for (index = VADDR_TO_PTENT(start); index < 1024 && start < end;
index++, start += B_PAGE_SIZE) {
page_table_entry entry = pt[index];
if ((entry & X86_PTE_PRESENT) == 0) {
// page mapping not valid
do {
int index = VADDR_TO_PDENT(start);
if ((pd[index] & X86_PDE_PRESENT) == 0) {
// no page table here, move the start up to access the next page
// table
start = ROUNDUP(start + 1, kPageTableAlignment);
continue;
}
TRACE("protect_tmap: protect page 0x%lx\n", start);
struct thread* thread = thread_get_current_thread();
ThreadCPUPinner pinner(thread);
// set the new protection flags -- we want to do that atomically,
// without changing the accessed or dirty flag
page_table_entry oldEntry;
while (true) {
oldEntry = X86PagingMethod32Bit::TestAndSetPageTableEntry(
&pt[index],
(entry & ~(X86_PTE_PROTECTION_MASK | X86_PTE_MEMORY_TYPE_MASK))
| newProtectionFlags
| X86PagingMethod32Bit::MemoryTypeToPageTableEntryFlags(
memoryType),
entry);
if (oldEntry == entry)
break;
entry = oldEntry;
page_table_entry* pt = (page_table_entry*)fPageMapper->GetPageTableAt(
pd[index] & X86_PDE_ADDRESS_MASK);
for (index = VADDR_TO_PTENT(start); index < 1024 && start < end;
index++, start += B_PAGE_SIZE) {
page_table_entry entry = pt[index];
if ((entry & X86_PTE_PRESENT) == 0) {
// page mapping not valid
continue;
}
TRACE("protect_tmap: protect page 0x%lx\n", start);
// set the new protection flags -- we want to do that atomically,
// without changing the accessed or dirty flag
page_table_entry oldEntry;
while (true) {
oldEntry = X86PagingMethod32Bit::TestAndSetPageTableEntry(
&pt[index],
(entry & ~(X86_PTE_PROTECTION_MASK
| X86_PTE_MEMORY_TYPE_MASK))
| newProtectionFlags
| X86PagingMethod32Bit::MemoryTypeToPageTableEntryFlags(
memoryType),
entry);
if (oldEntry == entry)
break;
entry = oldEntry;
}
if ((oldEntry & X86_PTE_ACCESSED) != 0) {
// Note, that we only need to invalidate the address, if the
// accessed flag was set, since only then the entry could have
// been in any TLB.
InvalidatePage(start);
}
}
} while (start != 0 && start < end);
if ((oldEntry & X86_PTE_ACCESSED) != 0) {
// Note, that we only need to invalidate the address, if the
// accessed flag was set, since only then the entry could have been
// in any TLB.
InvalidatePage(start);
}
}
pinner.Unlock();
goto restart;
return B_OK;
}